Justin Hartwig has been in the league for nine years now, so he is well aware how difficult it is to be a center in the NFL.

Even if the Steelers used the 18th overall pick on center Maurkice Pouncey as the heir apparent, Hartwig knows that stepping in and playing center just out of college is borderline impossible.

"It would be difficult for a rookie center to come in and play in this system, however, it is not saying that it couldn't be done," Hartwig said.

» Nagging injuries continue to mount for the Steelers, as running back Rashard Mendenhall and rookie linebacker Jason Worilds left practice yesterday with minor dings. Mendenhall injured a toe when he was stepped on, and Worilds left with a hamstring injury. RB Jonathan Dwyer (hamstring), LB Andre Frazier (knee), NT Casey Hampton (hamstring), OL Ramon Foster (concussion) and Pouncey (hamstring) also sat out of afternoon practice, but all are close to returning, according to coach Mike Tomlin.

» The Steelers released FB Demetrius Taylor and signed second-year FB Dwayne Wright off waivers from Philadelphia.

» Isaac Redman caught the eyes of many last year for his goaline work during the preseason. Redman was the topic of conversation after Sunday's "Backs on Backers" drill. Tomlin played some of Redman's blocks to the team during meetings and then awarded Redman the winner of the drill.